This invention concerns apparatus suitable for delivery of stents to body cavities.
In general, stents are prosthetic devices which can be applied within a body cavity, for example, a blood vessel of the body of a living human, or in some other difficultly accessible place. The prosthesis is formed of a tubular body, the diameter of which can be decreased or increased. Stents are particularly useful for permanently widening a vessel which is either in a narrowed state, or internally supporting a vessel damaged by an aneurysm. Such stents are generally introduced to the body cavity by use of a catheter.
For example, Zollikofer et al., 167 Radiology 707 (1988), describes introduction of a self expanding stent (the Wallsten prosthesis) over a catheter. The stent is restrained to the catheter by a doubled over membrane, which is withdrawn when the stent is in the appropriate location by use of a sliding release device. Wallsten, U.S. Pat. No. 4,685,771, 1987, describes introduction of a prosthesis on a catheter, the prosthesis being held by gripping means. The prosthesis is expanded by pushing one of the gripping means toward the other so that a balloon-like shape is achieved. The quipping means are then released by use of a wire running the length of the catheter. Palmaz et al., 156 Radiology 73 (1985) and U.S. Pat. No. 4,733,665, describe introduction of a stent over a balloon catheter. The stent is held in place by oversized tapered leading and trailing retainers. These retainers appear to be an integral part of the balloon of the catheter.